1. Field of the Invention
The present invention is directed to a method for the operation of a magnetic resonance apparatus for functional imaging, of the type wherein a number of images without and with a designational stimulation of the examination subject are sequentially registered in successive alternation.
2. Description of the Prior Art
Functional imaging offers the possibility of being able to examine and observe body or organ functions over a longer time span in order to obtain information about possible pathologies of the examination region. A number of image sequences are successively registered in alternation within the framework of these examinations, with a designational stimulation of the examination subject either being emitted or not emitted within the respective sequence. As a result of the designational stimulation, stimulation-dependent differences appear in the registered images, these differences being processed within the framework of the evaluation that ensues after the registration of a respective image. One example of an examination method for functional imaging is BOLD (blood oxygen level dependent) measurement using a magnetic resonance apparatus, whereby activity images of the brain of the patient are registered. For some of the measurements, the brain of the patient is thereby stimulated, for example as a result of finger movement, acousto-optical signals, electrical pulses, etc., whereas no stimulation ensues during the others of the measurements. The different measurements that are obtained in the framework of the evaluation are correlated with respect to an evaluation correlation value. A measure for the stimulation of defined brain areas of the patient are obtained from this evaluation, with the stimulated brain areas appearing in the evaluation image as clearly brighter regions.
In known methods, the evaluation ensues directly after a measurement or registration of an image. This evaluation is based on the relevant information known at this moment as to whether the respective image was registered with or without stimulation, possibly also with information relating to the stimulation as well as the respective evaluation correlation value. Problems arise, however, when a repeated evaluation is to ensue at a later point in time. It is not possible to exactly allocate the image-related, relevant information such as a stimulation phase underlying the registration as well as the information about the stimulation itself and the evaluation correlation value to the respective image.